This map try to show us the sky quality useable by a training observer.

Precautions of interpretation :
This map is good only for a zenithal cone of 50° (from the vertical of a precise location) and don’t show the light pollution toward the horizon.

To consider the value indicate on the map, it’s understood that the observer may have not to be expose himself to a direct light source and he have to be sheltered from a direct light source.

The precision of the data are not guarantee : this is indicated values and obtain with arithmetic and non-based from reality. Locals phenomenas as lighting of monuments or public buildings, or at the contrary the extinction of the light from a certain time can elude the data.
This map show the light pollution at the time of 23:00, during winter, with a midle quantity of humidity around 85 percent. The highway, due to the cars light are systematicaly counted as a source of light pollution. Moreover, the glowing due the cars crossing can reduce to nothing around 20 minutes the nocturn vision of the observer and the quality of the local seeing. Aquatic places don’t have to be take in consideration : the light propagation of the light glare was voluntary reduce in a clearness concern. This map show the urban places : artisanal places, industrial places, residential places and some big building (nuclear central i.e).
The elevation play a dominant role on the light propagation : more the observer is high, less the light diffusion is important. In this way, a city located below an observation point at 1000m higher will affect less the air quality for the observer contrary to if this last was been in plain (at the same level of the light source).
The effect of the elevation are semi-logarithmic : the first thousand of meters have an important role on the air quality.

White : 0-15 visible stars (without planets) according to the conditions. Very high level of light pollution and all around. Typical of big urban centre and big regional and national cities.

Red : 80-150 stars : constellations and others stars appears. In a telescope, Some Messier object began to be observable.

Orange : 150-250 stars in good conditions. The light pollution is present all around but some darks areas appears. Typicaly the middle suburbs.

Yellow : 250-500 stars. Strong light pollution but the Milky Way can appear in good conditions. Some Messiers among the most bright can be visible with the necked eye.

Green : 500-1000 stars : far peacefull suburbs, Milky Way many times visible but very sensitive to the atmospheric conditions. Typicaly, the glare of light pollution take a large place in the sky and reach at 40-50° of elevation.

Cyan : 1000-1500 stars. The Milky Way is visible most of the time in fonction of climatic conditions but without contrast.

Blue : 1500-2000 stars. Good sky. The Milky Way is easily visible, we began to have the sensation of a good sky, but, some source of light pollution damage the sky and in a second time the sky by reflexion at the vertical of the observer.

Night blue : 2000-3000 stars. Very good sky. The Milky Way is present and powerfull. The light glares are far away and scaterred, they don’t affect the sky quality.

Black (green by texture transparency) : more than 3000 stars. No light pollution problems revealable on the sky quality

1 This maps are and rest the exclusive property of Frederic Tapissier / AVEX or its beneficiary.

2 The author give the authorization to diffuse this map only in a private context.

3 The rights can’t to be transfer by the user to nobody and for any reason.

4 All print demand, diffusion must have to be approove by Frederic Tapissier / AVEX.

5 No modification of the data, particulary the colors and the range of samples, the exploitation size of this map can not be operate without the autorization of Frederic Tapissier.

6 This PDF is protect by Copyrights and others electronics marks, and is protect against modifications and the exptortations of the containing data.

7 The author can not be consider as responsable of the use of this data in any way.

8 The author did not garantee the precsion of the data who are approximatives, the values are obtaining by arithmetic. This document can not be consider as an official basis for any works, and decline any responsability past, present and future of the using and the interpretation of this data.

also availabe : special map for astrophotography optimised

You can use this map with GRESAC (index book of most famous astronomical place in france)